Re: [Confuse-devel] cant get the result after callback function

[Martin Hedenfalk]

Hi,

Short answer:
*(char **)result = value;

Longer answer:
The void *result argument is a pointer to storage for the value. A void 
pointer is used so the same callback function type can be used for all 
sorts of options. For integers the void * must be casted to an int * 
(or actually a long int *). For a string (ie, a char *) it must be 
casted to a char **. For strings this is a pointer to a pointer.

If you assign a value to (char *)result, all that is changed is the 
pointer passed to the callback function. If you instead assign to 
*(char **)result, you assign to the string (character pointer) pointed 
to by the result pointer.

/martin

tisdagen den 21 oktober 2003 kl 19.09 skrev .:

> Hi all.
>
> A have a callback function that changes the result value. I have tried
> some methods to return new result, but when i do cfg_getstr() i always
> got NULL.
>
> I tried:
>
> 1) (char*)result=value;
>
> 2) result=(char*)calloc(1,strlen(value)+1);
>    strncpy(result,value,strlen(value));
>
> 3) static char *newstr;
>    ...
>    newstr=(char*)calloc(1,strlen(value)+1);
>    strncpy(newstr,value,strlen(value));
>    result=newstr;
>
> How to store the string into *result pointer inside callback
> function ?
>
> --
> Best regards,
>  .                          mailto:address@hidden